More intake than extract? Bad?

Blenko420

Well-Known Member
Hey guys another noob question from a noob. Atm im running an ac unit ducted into my tent with 6inch ducting with a 6inch inline fine at the end to boost the cold air flow. However my carbon filter and extractor fan is only 5inch. I can tell that the intake is out doing the extractor because my tent walls are sort of puffing out my question is. Is that bad? Any advice and info greatly appreciated as always thanks.
 

Dynamo626

Well-Known Member
not bad at all. much better than the walls sucking in which is hard on the tent. if you put a dust shroom over the intake than the possitive pressure will help keep pests and pathogens out. just make sure your extracter fan are matched. fan cfm cant be more than that of the filter, and not less than half the cfm of the filter.
 

Blenko420

Well-Known Member
Not much chance of pests getting through the intake its ducted directly from my ac unit but yeah thats what i was thinking southcross the smell will be pushed out rather then passing through the carbon filter im 24 days into veg since potting my clones they already produce a smell but im guessing not even close to what they will produce during flower. Would you suggest a larger extractor fan and filter (i hope not just paid 70 pound for the filter lol) i do have 2 oscelating fans moving air around within do you think that could be contributing to the walls of the tent puffing out?
 

Blenko420

Well-Known Member
not bad at all. much better than the walls sucking in which is hard on the tent. if you put a dust shroom over the intake than the possitive pressure will help keep pests and pathogens out. just make sure your extracter fan are matched. fan cfm cant be more than that of the filter, and not less than half the cfm of the filter.
How do i find out the cfm of my fan and filter?
 

Blenko420

Well-Known Member
Some pics for a better idea of the setup only got 2 lights running atm will switch to 3 when they out grow their boundaries. Vegging as long as possible before flowering have marked out max height for veg within the tent. 3 of my plants are smaller than the others (poor transportation) have started training 5 of them. The other one in a day or so. Sorry light is on.
 

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Blenko420

Well-Known Member
Most ratings are standard from the manufacturer. According to the diameter. Whoever sold the 5" stuff should have include what cfm it's rated at. If they didn't, somebody else that sells similar sized stuff will.

Then plug those numbers into this to dial in the system,

https://www.easycalculation.com/unit-conversion/cfm-calculator.php
Thats the thing i didnt buy it the fan i sourced it from a friend who wasnt using it came with a filter too but the filter was burnt out it already smelt like weed and when i connected it to the fan smelt even worse so i bought a new filter.
 

SouthCross

Well-Known Member
Thats the thing i didnt buy it the fan i sourced it from a friend who wasnt using it came with a filter too but the filter was burnt out it already smelt like weed and when i connected it to the fan smelt even worse so i bought a new filter.

What's getting me. I've never seen a 5" fan or a 5" filter. Industry standard is 4",6",8"10". Never came across anything in five inches.

If it's a 6". It's about 400 cfm on the filter. Probably 430 cfm on the blower.
 

Blenko420

Well-Known Member
No wonder. Different countries. I keep forgetting this is an international website. Email the guy. Ask what it's rated for. I searched Bing and didn't come up with anything 5". And why is it 5"??? I thought you guys used metric???
Haha indeed we do. However, i prefer to work in inches. Im a roofer by trade and was taught in imperial hence my preference.
 

Dynamo626

Well-Known Member
The major issue would be the positive pressure pushing out smell.
didnt even think of that have a buddy that runs pos pressure never noticed the scent but honestly he isnt the best gardener lol. if scent became an issue then you can get a cheep fan speed controler for the intake fan will allow you to dial in the intake
 
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